APA (7th ed.) Citation

United States. National Park Service. (1989). Summer trail development: Voyageurs National Park. The Service.

Chicago Style (17th ed.) Citation

United States. National Park Service. Summer Trail Development: Voyageurs National Park. [Washington, D.C.?]: The Service, 1989.

MLA (8th ed.) Citation

United States. National Park Service. Summer Trail Development: Voyageurs National Park. The Service, 1989.

Warning: These citations may not always be 100% accurate.